---
title: Adding rewrite content rules
description: Add rewrite content rules, which modify text in HTTP response bodies as it's served to the client in PingAccess. The most common use case for this rule is to rewrite host names within URLs contained in HTML, JavaScript, or CSS content.
component: pingaccess
version: 9.0
page_id: pingaccess:pingaccess_user_interface_reference_guide:pa_adding_rewrite_content_rules
canonical_url: https://docs.pingidentity.com/pingaccess/9.0/pingaccess_user_interface_reference_guide/pa_adding_rewrite_content_rules.html
revdate: October 7, 2025
section_ids:
before-you-begin: Before you begin
steps: Steps
rewrite-content-rule-examples: Rewrite content rule examples
---
# Adding rewrite content rules
Add rewrite content rules, which modify text in HTTP response bodies as it's served to the client in PingAccess. The most common use case for this rule is to rewrite host names within URLs contained in HTML, JavaScript, or CSS content.
Rewrite content rules use a subset of the Java regular expression syntax that excludes look-behind constructs, such as `\b`, and the boundary matcher, `\G`. If you don't use Java regular expression syntax, the rule performs a case-sensitive search and replace operation.
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| - | --------------------------------------------------------------------------------------- |
| | Extensive use of rewrite content rules might have significant performance implications. |
This rule supports content that's either chunked or streamed from the target server. When sent to the client, the content is always chunked.
## Before you begin
Confirm that you aren't using the [agent](../introduction_to_pingaccess/pa_choose_a_deployment_model.html#agent) model. Rewrite content rules aren't available for agent deployments.
## Steps
1. Click **Access**, then go to **Rules > Rules**.
2. Click **[icon: plus, set=fa]Add Rule**.
3. In the **Name** field, enter a unique name up to 64 characters long.
Special characters and spaces are allowed.
4. In the **Type** list, select **Rewrite Content**.
5. To define what type of response data to apply the rewrite rule to, enter one or more **Response Content-Types**.
The default values are `text/html`, `text/plain`, and `application/json`. The list is an ordered list.
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| | * Only text-based content types are supported.
* Text-based content types compressed with gzip, deflate, or compress will decompress before rewrite rule processing. However, the content isn't re-compressed before it's sent to the client. |
6. Define one or more sets of **Find and Replace Criteria**.
If you specify multiple criteria, each operation is performed against the original content, effectively applying the rule concurrently.
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| | Changes can affect CSS, Javascript, and other text-based elements served to the client. Make sure to craft the regular expression properly to avoid unintentionally modifying content. |
7. If the protected application doesn't return a **Content-Type** header, select **Missing Content-Type Allowed**.
8. If you enable **Missing Content-Type Allowed**, specify the encoding that the application returns in the **Missing Content-Type Charset** field.
This field could contain `UTF-8`. A list of valid values is available in the [Oracle Java 8 SE Technical Note](https://docs.oracle.com/javase/8/docs/technotes/guides/intl/encoding.doc.html).
9. If necessary, increase the size of the buffer used to perform the replace operation by clicking **Show Advanced** and entering a value in **Maximum Buffer Size**.
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| - | ------------------------------------------------------------------------------------------------------------------------------------------ |
| | Replacement values can't be larger than the buffer size. The minimum buffer size you can specify is 1024 bytes. There is no maximum value. |
10. Click **Save**.
## Rewrite content rule examples
This table provides examples of rewrite content rule use cases and their results.
| Example description | Original content | Content type | Find criteria | Replacement value | Modified text |
| ----------------------------------------------------------------- | ------------------------------------------------ | ------------------ | --------------------- | ----------------- | ------------------------------------------------ |
| Rewrite URL portion of a web link | `` | `text/html` | `serverx.inside.corp` | `www.acme.com` | `` |
| Case-sensitive text replacement | ACMEcorp | `text/html` | Ecorp | `E Corporation` | ACME Corporation |
| Value masking | ```
{
"origin": "127.0.0.1, 192.168.1.1"
}
``` | `application/json` | `(127.0.0.1, ).*"` | `***********"` | ```
{
"origin": "127.0.0.1, ***********"
}
``` |
| Replacing text inside a specified element using Java regex groups | This text is **bold**. | `text/html` | `(bold)` | `not $1` | This text is not bold. |
| Case-insensitive text replacement using a Java regex match flag | HTTP | `text/html` | `(?i)http` | `FTP` | FTP |